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https://issues.apache.org/jira/browse/LUCENE-9154?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17027277#comment-17027277
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Ignacio Vera commented on LUCENE-9154:
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Let's put a different angle.
Imagine that instead of using the current encoding, we have chosen to use
floats instead so we keep the encoding's size to 4 bytes. In that case I guess
we would have chosen to define all our bounding boxes using floats instead of
doubles and it won't be so polemic (we are currently doing so in XYShape). Or
do you think we would still try to match doubles against floats?
LatLon encoding is our custom way to represent numbers in the domain space so
we keep a constant error as well as avoiding numerical issues that you might
have with floats (see LUCENE-9139). But then I do not really understand why we
are trying to match our custom numerical representation against full doubles.
> Remove encodeCeil() to encode bounding box queries
> ---------------------------------------------------
>
> Key: LUCENE-9154
> URL: https://issues.apache.org/jira/browse/LUCENE-9154
> Project: Lucene - Core
> Issue Type: Improvement
> Reporter: Ignacio Vera
> Priority: Major
> Time Spent: 10m
> Remaining Estimate: 0h
>
> We currently have the following logic in LatLonPoint#newBoxquery():
> {code:java}
> // exact double values of lat=90.0D and lon=180.0D must be treated special
> as they are not represented in the encoding
> // and should not drag in extra bogus junk! TODO: should encodeCeil just
> throw ArithmeticException to be less trappy here?
> if (minLatitude == 90.0) {
> // range cannot match as 90.0 can never exist
> return new MatchNoDocsQuery("LatLonPoint.newBoxQuery with
> minLatitude=90.0");
> }
> if (minLongitude == 180.0) {
> if (maxLongitude == 180.0) {
> // range cannot match as 180.0 can never exist
> return new MatchNoDocsQuery("LatLonPoint.newBoxQuery with
> minLongitude=maxLongitude=180.0");
> } else if (maxLongitude < minLongitude) {
> // encodeCeil() with dateline wrapping!
> minLongitude = -180.0;
> }
> }
> byte[] lower = encodeCeil(minLatitude, minLongitude);
> byte[] upper = encode(maxLatitude, maxLongitude);
> {code}
>
> IMO opinion this is confusing and can lead to strange results. For example a
> query with {{minLatitude = minLatitude = 90}} does not match points with
> {{latitude = 90}}. On the other hand a query with {{minLatitude =
> minLatitude}} = 89.99999996}} will match points at latitude = 90.
> I don't really understand the statement that says: {{90.0 can never exist}}
> as this is as well true for values > 89.99999995809048 which is the maximum
> quantize value. In this argument, this will be true for all values between
> quantize coordinates as they do not exist in the index, why 90D is so
> special? I guess because it cannot be ceil up without overflowing the
> encoding.
> Another argument to remove this function is that it opens the room to have
> false negatives in the result of the query. if a query has minLon =
> 89.999999957, it won't match points with longitude = 89.999999957 as it is
> rounded up to 89.99999995809048.
> The only merit I can see in the current approach is that if you only index
> points that are already quantize, then all queries would be exact. But does
> it make sense for someone to only index quantize values and then query by
> non-quantize bounding boxes?
>
> I hope I am missing something, but my proposal is to remove encodeCeil all
> together and remove all the special handling at the positive pole and
> positive dateline.
>
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